Telephone receiver



Nov. f3, 1925. 1,559,597

J. A. WILLIAMS TELEPHONE RECEIVER Filed May l. 1922 Patented Nov. 3,' 1.925.

J' OSEPH A. WILLIAMS, 0F CLEVELAND, OHIO.

TELEPHONE RECEIVER.

Application filed May 1,

provide a receiver which is sensitive to very small currents in the receiver coil.

Still further the invention aims to provide a construction wherein there is a strong permanent magnet flux and wherein the number of .turns of the receiver coil may be increased and the resistance per' turn decreased.

In one aspect the invention relates to a receiver wherein there are a plurality, i. e., two or more coils for a magnetic pole of the permanent magnet or series of permanent magnets having the same or a common magnetic pole.

In another aspect the invention relates to the arrangement of a series of magnets or parts of a multipart magnet in a cup-shaped housing with one magneticpole at the central part of the`base of the cup and the other pole at the openend of the cup.

VAs additional features o f the inventionl the ends of the magnet parts are ljoined by a ring serving as an annular or continuous flux distributor to be engaged by the periphery of the vibra-tory diaphragm, this ring constituting a pole piece for one magnetic pole, and the multiplecoils with their 4 cores being arranged at the other magnetic pole, i. e., at the central part of the cup, and projecting upward therefrom y toward the central part of the diaphragm. f

As another important feature the permanent magnet parts are preferably embedded in materialforming the cupshaped housing.

Still another important feature of the invention consists in the arrangement of the plural receiver coils with their cores in the form of a unit and removable as such should a coil become damaged.

The invention may be further briefly sum` marized as consisting in certain vnovel del tails of construction, and combinations and formed. of bakelite,

1922. Serial No. 557,583.

arrangements of parts which will be described in the specification and set forth in the appended claims.

In the accompanying sheet of drawings wherein I have shown thepreferred lform and a slight modification of the invention, Fig. 1 is a sectional view, the section being taken through thecenter or axis of the receiver, substantially along the line 1-1 of Fig. 2; Fig. 2 is a transverse sectional view along the line 2-2 of Figl, looking in the direction indicated by the arrow`s;`Fig. 3 is a side elevation of the same with the cap and diaphragm removed, part vof the housing being broken away; Fig. 4 is a top plan view with the'cap and diaphragm removed; Fig. 5' is av perspective view showing by solid lines the arrangement of the permanent magnet 'parts and soft iron ring at the upper endsthereof, with the housing it-v self' shown by dotted lines; and Fig. 6 is a v iew similar .to F ig.'1, showing a modification, the section being taken through the walls of the housing vinstead of through the magnets as in Fig. 1..

In the embodiment of the invention herein illustrated, there is a cup-shaped housing 10 of insulating material which may be hard rubber or other suitable material. Embedded in the inner wall of the housing 10 are a series of permanent magnets 11 whichextend down the cylindrical wall ofthe housing to the base and then inwardly toward the center where they unite to form one permanent magnet po e bedded lin place, is a ring orA annulus 12, which is preferably formed of soft iron. This ring engages the upper ends of the `magnets or magnet parts 1'1 and connects screwed onto the exteriorly threaded part of the ring v12. The diaphragm 13 is constructed as described in my vcopending application, Serial No. 555,821, filed April 21, 1922, being so tapered from the center to At the top of the housing 10and also em rying capacity from the center to adjacent 4 the periphery thereof.

Referring again .to the permanent mag. nets 11, Ait will be observed that in thls instance they extend in straight lines down the cylindrical part of the cup 10, but in the base they'do not extend inwardly in straight radial lines, but in the base are given a curved shape so as to give increased length thereto, and therefore increased magneto motive force.

It will be observed that with these several magnets having a common magnetic lpole at the central` part of the base of the cup, and with the other magnetic pole at the open end of the cup, vthe. arrangement is such as to produce the eect of one multipart magnet. It might be stated, therefore, that I do not desire to be limited to a construction wherein the magnet parts are formed separately.` That arrangement 1s now preferred by me, but it may be found Y desirable to form the magnet parts in one or two parts in the event the magnet has four branches or legs. Furthermore, it may be desirableto vary the number of branches or legs, i. e., to provide more or less than' two branches.

In this instance the magnetic pole at the central part of the base of the cup is represented as the south ole and themagnetic poleof the upper enA s of the magnet parts or ofthe ring 12 is represented as the north pole, but it will be understood that if desired the polarity may be the reverse of that indicated in the drawings. v

As before stated, an important feature of the invention resides in the provision of a plurality, i. e., two or more receiver. coils for one magnetic pole of the permanent magnet or magnets, this pole being witli the construction shown, at the central part of thebase of the cup; Though I do not wish to be limited to the use of four receiver coils since in some constructions I may employ for a magnetic pole less than four coils, and in other constructions possibly more than four coils, I haveA in the ,drawings illustrated four receiver coils, the same being designated 15. These coils are preferably circular, i. e., cylindrical, for when so formed there isless resistance per turn than when given an elongated cross section of the same area, or, in fact, formed in any lother shape than cylindrical. These coils in 7practice are connected in series, the result being that I secure a large number of turns with low resistance per turn sothat when the coils are traversed by even feeble` currents a greater ampere turn value is obtained than with any prior arrangement or construction of which I am aware, so that with my present arrangement increased sensitiveness is obtained.

The coils 15 surround individual cores 16, which at their upper ends engage and are united to a pole piece 17, located centrally of the receiver close to the diaphragm 13, and at their lower ends the cores engage and are united to a pole piece 18 which contacts with the inner-central ends of the permanent magnets or permanent magnet parts 11 the cores 16 and pole pieces 17 and 18 being preferably formed of `soft iron.

Preferably the coils 15, cores 16 and pole pieces 17 and 18 are made up as a unit de'- signed to be inserted and secured in the cup, or to be removed as -an entirety therefrom, and though the parts `can be fastened together in various. ways, in this instance the cores andpole pieces are fastenedtogether. by upsetting the ends of the cores 16 which therefore serve as rivets.Y YThe lower pole piece 18-can be and preferably is flat, and the upper pole piece 17 is preferably provided inside the upset ends of the cores 16 with an annular elevated portion, theupper face of which is close to the diaphragm 13. In the embodiment shown in `1 the unit is fastened in place to the base of the hous- A'ni ing by a short threaded stud 19 whose inner end is riveted tothe center of the lower pole piece 18, the ybody of the ystud extending through an opening formed in the 1nner ends of the permanent magnet parts 11 v preferably molded in the housing 10 along,

with the permanent magnet or magnet parts 11 and in contact with the inner ends of the latter, and this pole piece is preferably provided with a threaded boss 18b which extends through an opening inthe base of the housing* and receives a Vclamping nut `18.

In this instance theupper pole piece 17a and the cores 16 are held to the lower pole ,piece 18a by a central screw 21 which .eX- tends centrally through the upper pole :piece 17a and is screwed into a threaded opening extending through the` boss 18":-11With this construction, should it be desired to remove any of the coils,`the screw is removed and the upper pole piece. is lifted out of place, permitting the coils to be slipped from the cores. v y

The terminals of the series of coils maybe brought out fromthe receiver in any suitable way, andif desired, when the coil unit of Fig. 1 is employed, provision may be made by suitable @Ontacts for connecting and disconnecting the coils from the terminals when the unit is slipped into place or removed.

Thus it will be seen that I have provided a novel form of receiver having many improved features which co-operate to form a receiver which is very sensitive to minute currents, thus making it especially useful for wireless work.

Having described my invention, I claim':

l. In a telephone receiver, a cup-shaped housing formed of insulating material and4 having a plurality of permanent magnet elements embedded therein and extending from near the open end of the housing downwardly toward the base and inwardly along the base toward the center, said elements having similar magnetic poles adjacent the axis of the housing.

2. In a telephone receiver, a cup-shaped housing of insulating material having on the inside thereof permanent magnet elements extending down from near the open end of the housing to the base and inwardly along the base toward the center thereof in curved lines to provide additional length, a diathe center of the base,

phragm closing the open end of the housing, and a coil having a core projecting upwardly from the base toward the central part of the diaphragm.

3.v A telephone receiver comprising a cuplike housing containing a coil and a core, said housing having a plurality of permanent magnet elements extending from the open end to the base and across the base to adjacent the center, said magnet elements having similar magnetic poles adjacent the open end and similar magnetic poles adjacent a ring of magnetic material joining the ends of said elements at the open end of the housing, a flexible metal diaphragm closing the open end of the housing and engaging 'said ring, said diaphragm tapering from the center toward the periphery and having substantially the same flux carrying capacity from the central part opposite the core to the peripheral part adjacent the edge of the housing.

In testimony whereof, I hereunto affix my signature. l

JOSEPH A. WILLIAMS. 

